The present disclosure relates to a portable information processing device which has, for example, a USB (Universal Serial Bus) communication function which is attachable to and detachable from a receptacle of a personal computer (PC) or the like.
As an interface for connecting electronic equipment, such as a PC or the like, to a device, such as a mouse or a keyboard, the USB standard which is a serial interface standard for which the specification is defined by USB-IF (USB-Implementers Forum) has been widely employed.
The USB standard sets a standard A plug as the connection part of a device. As shown in FIG. 1, the standard A plug 1 includes four connection terminals, a circuit ground terminal 2, a circuit power supply terminal 3, a first data communication terminal 4, and a second data communication terminal 5.
The standard A plug 1 is inserted so as to be fitted into a standard A receptacle of a USB mounted on electronic equipment such as a PC, and it is thereby possible to give a connection state (USB connection) based on the USB standard to the electronic equipment as a host and the device.
In addition, in recent years, in accordance with the widespread use of the USB standard in the PCs, portable USB memory devices having a standard A plug 1 at one end side have been widely distributed.
The portable USB memory device (USB device) is inserted so as to be fitted in the standard A receptacle mounted on the PC, and is USB-connected to the PC.
Thereby, the USB memory device stores data sent from the PC or outputs stored data to the PC via the standard A plug 1 in response to a request from the PC (for example, refer to Japanese Unexamined Patent Application Publication No. 2004-78879).
In addition, the USB plug is generally also called a USB connector.
The above-described USB device includes a circuit board portion which integrally mounts electronic circuits such as semiconductor chips with the USB connector thereon. The circuit board portion is contained in a casing made of a molded resin or the like.
In the USB device as well, in order to protect the electronic circuits such as semiconductor chips, countermeasures against electro-static discharge (ESD) are important, and various countermeasures have been proposed (for example, refer to Japanese Unexamined Patent Application Publication No. 2007-193523).